A benefit of the Hybrid Instance cluster is that it reduces the cluster startup time significantly because the Core Node Instance group always contains On-Demand Instances. In this case, the cluster can spin up quickly, even if the Task Node Instance group has not started yet. Because Task Nodes are optional in the cluster and always defined as Spot Instances, they are subject to both availability and the maximum bid price, should it exceed the market price. If those conditions are not met, the Task Node Instance groups do not start. But if the Core Node Instance groups have already started, then the Pipelines run immediately. In contrast, clusters with Spot-only instances cannot start up if the specified Spot instances are not available, because all the Core Node instances would use the Spot instance type.
- In terms of cost, typically the Hybrid Instance cluster can be more expensive than Spot cluster and less expensive than On-Demand Cluster.
- In the performance, the Hybrid Instance cluster is typically better than Spot or On-Demand Instance clusters if the Task Nodes are running.
- In terms of reliability, it is far better than Spot Only Instances and equally reliable as the On-Demand Instances.
- In terms of the start up time, the Hybrid cluster starts up much faster than a Spot Cluster and at almost the same speed as that of the On-Demand cluster.
If you do not select the Hybrid option on the Advanced Tab, then the instance type specified in the Settings tab is used as the same Instance Type for all three of the following node groups.